VARIABLE UPTAKE OF TRITIATED OESTRADIOL BY THE ANTERIOR HYPOTHALAMUS IN THE POSTPUBERTAL FEMALE RAT

1969 ◽  
Vol 61 (4) ◽  
pp. 585-591 ◽  
Author(s):  
Junzo Kato ◽  
Machiko Inaba ◽  
Takashi Kobayashi
Keyword(s):  
Mechanism Of Action ◽  
Anterior Hypothalamus ◽  
Oestrous Cycle ◽  
The Other ◽  
Female Rat ◽  
Physiological Regulation ◽  
Physiological Dose ◽  
Cyclic Changes

ABSTRACT Cyclic changes in phase with the oestrous cycle with regard to the amount of radioactive oestradiol taken up by the anterior hypothalamus were found in postpubertal rats following the injection of a physiological dose of tritiated oestradiol. Uptake at prooestrus was lower than that at dioestrus. In contrast no fluctuations in the concentration of the radioactivity in the other parts of brain, the hypophysis, and muscle or plasma were observed throughout the oestrous cycle. These findings suggest that the oestradiol receptor in the anterior hypothalamus of the rat is involved in the physiological regulation and maintenance of cyclical changes of the hypothalamo-pituitary system through the mechanism of action of feedback of oestrogen.

IN VITRO UPTAKE OF TRITIATED OESTRADIOL BY THE RAT ANTERIOR HYPOTHALAMUS DURING THE OESTROUS CYCLE

1970 ◽  
Vol 63 (4) ◽  
pp. 577-584 ◽  
Author(s):  
Junzo Kato
Keyword(s):  
Posterior Hypothalamus ◽  
Anterior Hypothalamus ◽  
Oestrous Cycle ◽  
Physiological Regulation ◽  
Cortex Cerebri ◽  
Anterior Hypophysis ◽  
Cyclic Changes ◽  
In Vitro Uptake

ABSTRACT The anterior, middle and posterior hypothalamus, the cortex cerebri, the anterior hypophysis, and the diaphragm of postpubertal rats at different phases of the oestrous cycle were incubated in vitro with tritiated 17β-oestradiol. Uptake of radioactivity by the anterior hypothalamus at prooestrus and oestrus was lower than that at dioestrus. In contrast no fluctuation in the concentration of the radioactivity in the other parts of brain, the hypophysis and muscle was observed during the oestrous cycle. These in vitro findings are consistent with the in vivo observations of cyclic changes in phase with the oestrous cycle of the amount of radioactive oestradiol taken up by the anterior hypothalamus following the injection of tritiated oestradiol (Kato et al. 1969b). Thus it is further suggested that the oestradiol receptor in the anterior hypothalamus of the rat is involved in the physiological regulation and maintenance of cyclic changes in the hypothalamo-pituitary system through the mechanism of action of feedback of oestrogen.

RNA SYNTHESIS IN THE RAT ANTERIOR HYPOTHALAMUS AND PITUITARY: RELATION TO NEONATAL ANDROGEN AND THE OESTROUS CYCLE

1970 ◽  
Vol 48 (1) ◽  
pp. 125-137 ◽  
Author(s):  
D. F. SALAMAN
Keyword(s):  
Ribosomal Rna ◽  
Anterior Pituitary ◽  
Rna Synthesis ◽  
Specific Activity ◽  
Gradient Centrifugation ◽  
Anterior Hypothalamus ◽  
Oestrous Cycle ◽  
Uridine Incorporation ◽  
Cyclic Changes

SUMMARY RNA from the anterior hypothalamus and anterior pituitary of rats has been labelled by incubation in vitro with [3H]uridine and characterized by density gradient centrifugation. A study of normal females during the oestrous cycle showed cyclic changes in [3H]uridine incorporation into rapidly labelled RNA (rl-RNA) both in the anterior pituitary and hypothalamus. In both tissues the specific activity of RNA was low at dioestrus and high at oestrus and metoestrus. In androgenized females, incorporation into hypothalamic rl-RNA was less than the oestrus—metoestrus level and similar to that at dioestrus, while incorporation into anterior pituitary rl-RNA was similar to the oestrus—metoestrus level and greater than at dioestrus. [3H]Uridine incorporation into ribosomal RNA (r-RNA) of anterior hypothalamus and pituitary was also demonstrated by incubation for 4 h. Under these conditions there was no effect of androgenization on hypothalamic r-RNA, but the specific activity of pituitary r-RNA was greater than normal.

EFFECT OF FEEDING ETHINYLOESTRADIOL FOR VARIOUS PERIODS BEFORE MATING ON REPRODUCTION IN THE HAMSTER

1972 ◽  
Vol 70 (3) ◽  
pp. 582-590
Author(s):  
B. K. Davis ◽  
I. Noske ◽  
M. C. Chang
Keyword(s):  
Single Dose ◽  
Pregnancy Rate ◽  
Fertility Control ◽  
Normal Pregnancy ◽  
Oestrous Cycle ◽  
The Other ◽  
Feeding Schedule ◽  
Crown Rump Length ◽  
Essentially Normal ◽  
Effect Of Feeding

ABSTRACT Ethinyloestradiol (EO) fed for various periods before mating to female hamsters affected the timing of mating and pregnancy rate. Slight effects on ovulation, foetal-crown rump length and resorption may have occurred, but effects on implantation were not apparent among pregnant hamsters. The response observed depended upon the feeding schedule adopted: hamsters fed 2.5 mg EO in a single dose, on day 3 before mating, mated normally but had a significantly lower pregnancy rate; on the other hand, animals fed 2.5 mg EO (0.21 mg/day) over three oestrous cycles, days 14–3 before mating, showed variations in the time of mating but had an essentially normal pregnancy rate; and, a group of hamsters who received the same total amount of EO (0.63 mg/day) over one oestrous cycle, days 6–3 premating, showed untowards effects by the steroid on both the timing of mating and pregnancy rate. The implications of these results are considered in relation to fertility control.

Modulation of the No Secretion in the Pichilan-Activated Murine Macrophage Cell Line, Malu

1995 ◽  
Vol 8 (3) ◽  
pp. 135-149
Author(s):  
N. Vallot ◽  
F. Boudard ◽  
M. Bastide
Keyword(s):  
Cell Line ◽  
Mechanism Of Action ◽  
Metabolic Pathways ◽  
The Other ◽  
Nitric Oxide Production ◽  
Murine Macrophage ◽  
Macrophage Cell Line ◽  
Macrophage Cell ◽  
Murine Macrophage Cell Line ◽  
Kinase C

The mechanism of action of pichilan, a (1->3)-β-D-glucan on nitric oxide production by a murine macrophage cell line, MALU cells, was examined. Different metabolic pathways were investigated in order to understand pichilan-induced NO secretion. We demonstrate in the present paper that neither the acid arachidonic metabolism, the cAMP nor Ca2+ accumulation occured in the pichilan mechanism of action on NO secretion. On the other hand, we observed that a phorbol ester, PMA, modulated the NO secretion. An inhibition of 36% of the NO secretion was observed; consequently, pichilan could regulate the NO secretion by way of the protein kinase C. Furthermore, we demonstrated that TNF production stimulated by pichilan activation induced NO secretion by MALU cells. TNF would be the main modulator of NO secretion by pichilan or LPS-activated MALU cells. Moreover, we can note that pichilan and LPS did not act similarly on nitrite secretion by MALU cells.

CAPILLARY BLOOD FLOW IN THE GENITAL TRACTS OF CONSCIOUS EWES: CYCLIC CHANGES AND THE EFFECT OF OVARIAN HORMONES

1977 ◽  
Vol 74 (2) ◽  
pp. 185-191 ◽  
Author(s):  
B. W. BROWN ◽  
P. E. MATTNER
Keyword(s):  
Blood Flow ◽  
Genital Tract ◽  
Significant Rise ◽  
Capillary Blood ◽  
Oestrous Cycle ◽  
Capillary Blood Flow ◽  
Low Levels ◽  
Cyclic Changes ◽  
Conscious Animals ◽  
Secondary Rise

The indicator fractionation technique with [86Rb]rubidium chloride as the indicator was used in conscious animals to determine the relative blood flow (RBF) as a measure of capillary blood flow in regions of the genital tract of cyclic ewes and of hormonally treated ovariectomized ewes. The RBF values in the ampulla, isthmus, uterus and cervix of cyclic ewes were markedly raised at pro-oestrus and declined thereafter to low levels during the remainder of the oestrous cycle. On Day 4 a small secondary rise in flow occurred in the ampulla and isthmus. In ovariectomized ewes, oestradiol induced high levels of RBF in the ampulla, isthmus, uterus and cervix whether the animals had been treated previously with progesterone or given concurrent small doses of progesterone. Though progesterone given alone caused a significant rise in RBF in the uterus, this effect appeared to be one occurring only during active re-growth of regressed tracts. The findings are discussed in relation to oestradiol inducing a stimulatory effect on RBF in the genital tract of the ewe around oestrus but not at Days 3–4 of the oestrous cycle.

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