FACTORS AFFECTING PERIPHERAL CORTISOL LEVELS IN UNRESTRICTED EWES

1973 ◽  
Vol 74 (2) ◽  
pp. 331-337 ◽  
Author(s):  
D. C. Thurley ◽  
K. P. McNatty

ABSTRACT Sheep were bled at frequent intervals over a period including cyclical oestrus activity, pregnancy and lactation. The changes in peripheral plasma cortisol levels in response to herding by better or less well trained dogs or by people were compared. In all cases the cortisol response took the form of a hump-backed curve. The height of this hump was lower when people drove the sheep than when dogs were used, and was lower during lactation than in late pregnancy.

1970 ◽  
Vol 48 (4) ◽  
pp. 599-614 ◽  
Author(s):  
L. E. DONALDSON ◽  
J. M. BASSETT ◽  
G. D. THORBURN

SUMMARY Progesterone concentrations in the peripheral plasma of cows were measured by a protein-binding radioassay method. The mean concentration was lowest at oestrus (0·44 ng/ml) and then increased to a maximum of 6·8 ng/ml about day 14 of the 21-day cycle. The concentration decreased rapidly during the last 4 days of the cycle, reaching low levels on the day before oestrus. There were no significant changes in progesterone concentration during oestrus. After ovariectomy the plasma progesterone concentration decreased to a very low level (< 0·4 ng/ml). After hysterectomy, progesterone concentrations remained high for longer than in a normal cycle. At puberty, plasma progesterone concentrations indicated cyclic ovarian activity before the first observed oestrus. Daily treatment of cows with oxytocin (0·4 u./kg body weight) from day 2 reduced the oestrous cycle length to 9 days, but did not significantly alter the slow increase in plasma progesterone concentration during the first 5 days of the cycle. Plasma progesterone concentrations decreased again after day 5 to low values. Plasma progesterone concentration during early pregnancy was similar to the luteal phase value (4–6 ng/ml), declined during mid-pregnancy and then increased to a maximum (7–8 ng/ml) at about 240 days gestation. The concentration declined 2–3 weeks before calving. During lactation progesterone concentrations were very low until the resumption of cyclic ovarian activity. The first post-partum cycle, whether accompanied by observed oestrus or not, was usually preceded by a small increase in plasma progesterone concentration 3–5 days before the start of the cycle. Undernutrition significantly increased plasma progesterone concentrations in mid- and late pregnancy. Undernutrition of non-pregnant cows increased progesterone concentrations during the luteal phase of the first cycle, but reduced it in later cycles.


1969 ◽  
Vol 115 (522) ◽  
pp. 575-580 ◽  
Author(s):  
A. Elithorn ◽  
P. K. Bridges ◽  
J. R. Hodges ◽  
M. T. Jones

In a previous paper (Hodges, Jones, Elithorn and Bridges, 1964) we reported on adrenocortical activity in depressed and schizophrenic patients as revealed by plasma cortisol levels before and after electro-convulsive therapy (E.C.T.). Close similarity was found between the two groups except for three depressed patients who appeared to show considerably higher cortisol levels after the treatment than did the remaining subjects. The patients were examined at random different treatments during the whole treatment course and it appeared possible, both that the observed cortisol response to E.C.T. might depend partly on which treatment of the series in a whole course was under examination, and also that the response of the illness to therapy might be a significant factor. It was therefore decided to observe in a number of subjects the response to successive treatments throughout courses of E.C.T.


1960 ◽  
Vol 11 (3) ◽  
pp. 364 ◽  
Author(s):  
RL Reid

Plasma cortisol levels in fed and fasted non-pregnant and in undernourished pregnant ewes were consistently less than 1.5 µg per 100 ml. Most values were considerably above this level in 20 field cases of pregnancy toxaemia, 31 of 52 values being greater than 3 µg per 100 ml. These levels must be regarded as abnormally high in sheep. Pregnancy toxaemia was induced in two experiments by fasting after a period of severe under nutrition and in two by fasting previously well-nourished ewes in the presence of severe psychological stresses. The onset of clinical signs was associated with marked increases above normal in plasma cortisol. In three experiments involving a total of 23 previously well-nourished ewes, 11 of which carried twins or triplets, only one mild case of pregnancy toxaemia was induced by complete fasting in late pregnancy for up to 6 days, in the absence of any additional environmental stress. Pregnancy toxaemia was readily induced in 24 of 38 ewes in three experiments when severe psychological stresses accompanied fasting in late pregnancy. Adrenal hypertrophy, indicating sustained adrenal hyperactivity, was most pronounced in field cases of pregnancy toxaemia induced primarily by sustained under nutrition. Fresh adrenal weights (total of two adrenals) averaged 6.7 g compared to 3.8 g in normal non-pregnant ewes. Mean plasma cortisol levels in ewes with pregnancy toxaemia were significantly correlated with fresh adrenal weight. The suggestions that abnormalities of carbohydrate and fat metabolism in ewes with pregnancy toxaemia are those of adrenal steroid diabetes, and that cerebral depression may be largely a consequence of a cortisol-induced inhibition of glucose utilization, are discussed in the light of the probable metabolic effects of cortisol in the undernourished pregnant ewe.


2017 ◽  
Vol 88 (10) ◽  
pp. 1629-1635 ◽  
Author(s):  
Ayaka Ono ◽  
Akihiro Matsuura ◽  
Yumi Yamazaki ◽  
Wakako Sakai ◽  
Kentaro Watanabe ◽  
...  

Reproduction ◽  
1999 ◽  
Vol 115 (2) ◽  
pp. 341-347 ◽  
Author(s):  
T. R. Koiter ◽  
H. Moes ◽  
N. Valkhof ◽  
S. Wijkstra

2021 ◽  
Vol 92 (1) ◽  
Author(s):  
Masato Aoyama ◽  
Minami Shioya ◽  
Yume Tsukamoto ◽  
Hitomi Hasegawa ◽  
Shoei Sugita

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