Presence of a Diurnal Rhythm in Fetal Prolactin Secretion and Influence of Maternal Nutrition

Neonatology ◽  
1989 ◽  
Vol 55 (3) ◽  
pp. 164-170 ◽  
Author(s):  
Nicole S. Bassett ◽  
Laura Bennet ◽  
Karen T. Ball ◽  
Peter D. Gluckman
Keyword(s):  
Diurnal Rhythm ◽  
Maternal Nutrition ◽  
Prolactin Secretion

Maternal nutrition, prolonged lactation and birth spacing in Ethiopia

1981 ◽  
Vol 13 (3) ◽  
pp. 261-268 ◽  
Author(s):  
R. Jane Wenlock ◽  
R. W. Wenlock
Keyword(s):  
Nutritional Status ◽  
Maternal Nutrition ◽  
Birth Spacing ◽  
Prolactin Secretion ◽  
Low Energy ◽  
Birth Intervals ◽  
Food Energy ◽  
Maternal Nutritional Status ◽  
Body Weights

SummaryData from 375 Ethiopian mothers show lactations of between 25 and 30 months in the majority, very prolonged even by African standards. Maternal nutritional status, as shown by body weights, was low due to very low food energy intakes. With frequent suckling already raising prolactin levels, these very low energy intakes may also result in yet more prolactin secretion. New pregnancies are delayed and birth intervals extended beyond normal African standards by all these factors.

Effects of altered photoperiod or maternal melatonin administration on plasma prolactin concentrations in fetal lambs

1989 ◽  
Vol 122 (3) ◽  
pp. 633-643 ◽  
Author(s):  
J. M. Bassett ◽  
N. Curtis ◽  
C. Hanson ◽  
C. M. Weeding
Keyword(s):  
Diurnal Rhythm ◽  
Maternal Plasma ◽  
Prolactin Secretion ◽  
Plasma Prolactin ◽  
Fetal Plasma ◽  
Plasma Melatonin ◽  
Long Day ◽  
Melatonin Administration ◽  
Fetal Lamb ◽  
Nocturnal Increase

ABSTRACT During winter (December to March), when late-pregnant ewes were maintained under an artificial long-day photoperiod (16 h light) for 3 weeks or more before insertion of fetal vascular cannulae between 118 and 120 days of gestation (full term, 147 days), plasma prolactin concentrations in their fetal lambs were significantly increased throughout the last 3 weeks of gestation in comparison with values in similar aged fetuses from ewes experiencing only the natural short-day (<9 h light) winter photoperiod. When additional lighting was given only after vascular cannulation, fetal plasma prolactin increased steadily from low values, characteristic of winter pregnancies, to high values, characteristic of long-day (16 h light:8 h darkness) pregnancies. Maternal plasma prolactin concentrations changed in a similar way. During summer pregnancies (>16 h light), plasma prolactin in fetal lambs was significantly reduced within 48 h when ewes were given melatonin by i.v. infusion for 14 h each night to simulate the winter duration of the nocturnal increase in plasma melatonin. Maternal plasma prolactin concentrations also decreased significantly when melatonin was given for 3 weeks, but not in a shorter experiment. Increases in fetal plasma prolactin were proportional to the basal prolactin concentration in fetuses injected i.v. with TRH or a dopaminergic antagonist, metoclopramide, to assess how photoperiod influenced the responsiveness of prolactin secretion to acute stimulation. The results confirm that photoperiod, rather than developmental maturity, is the principal determinant of plasma prolactin in the fetal lamb during the last third of gestation, and provide evidence that photoperiodic information is transmitted to the fetus through the diurnal rhythm of melatonin in the ewe. Journal of Endocrinology (1989) 122, 633–643

SPECIAL PROBLEMS IN TOXICITY TESTING OF LONG ACTING DEPOT CONTRACEPTIVES

1974 ◽  
Vol 77 (1_Suppla) ◽  
pp. S315-S354 ◽  
Author(s):  
F. Neumann ◽  
R. von Berswordt-Wallrabe ◽  
W. Elger ◽  
K.-J. Gräf ◽  
S. H. Hasan ◽  
...  
Keyword(s):  
Biological Effects ◽  
Histological Finding ◽  
Toxicity Testing ◽  
Prolactin Secretion ◽  
List Type ◽  
Human Species ◽  
Prolactin Plasma Level ◽  
Human Use ◽  
Long Acting ◽  
Reproductive Processes

ABSTRACT Two types of so-called "depot contraceptives", long-acting steroids which are of interest for human use, were studied in animals. Norethisterone oenanthate, mainly gestagenic in the human and other species, turned out to be predominantly oestrogenic in rats. This oestrogenicity caused indirectly, via an enhanced hypophysial prolactin secretion, the well-known hypophysial and mammary tumours in rats. Another synthetic gestagen, 4,6-dichloro- 17- acetoxy- 16α-methyl-4,6-pregnadiene-3,20-dione, which might be considered in its biological actions similar to preparations containing chlormadinone acetate or medroxy-progesterone acetate, induced no signs of oestrogenicity in dogs. It is surmised that its gestagenic influence indirectly, and probaby, via an enhanced hypophysial prolactin secretion caused "mammary nodules" in this "non-rodent" species. These studies have born out mainly two facts: A synthetic steroid, norethisterone oenanthate, exerted different biological effects in different species: it was a gestagen in the rabbit, whereas in rats, its predominant influence was oestrogenic. The hypophysial prolactin secretion was enhanced in various species by different mechanisms: in rats, the oestrogenicity caused an increased prolactin plasma level, whereas in dogs, a gestagen with obviously no inherent oestrogenicity, 4,6-dichloro-17-acetoxy-16α-methyl-4,6-pregnadiene-3,20-dione, converted the histological appearance of the anterior pituitary into a condition with a greatly increased number of eosinophils. This histological finding was interpreted as an indicator for a hypersecretion of prolactin. Hence, animal work with "gestagens" has only limited predictive value with respect to their possible effects in the human species. Therefore, inflexible recommendations are not helpful in solving the safety problem of long-acting steroids which affect primarily reproductive processes.

Modulation of prolactin secretion by contraceptive progestins in cultured rat pituitary cells in vitro

1988 ◽  
Vol 117 (4_Suppl) ◽  
pp. S188-S189
Author(s):  
L. KIESEL ◽  
T. RABE ◽  
D. SCHOLZ ◽  
V. KIRSCHNER ◽  
B. RUNNEBAUM
Keyword(s):  
Prolactin Secretion ◽  
Pituitary Cells ◽  
Rat Pituitary ◽  
Rat Pituitary Cells

Regulation of hypothalamic development by maternal nutrition

2015 ◽  
Author(s):  
Merly Vogt ◽  
Lars Paeger ◽  
Simon Hess ◽  
Sophie Steculorum ◽  
Susanne Neupert ◽  
...  
Keyword(s):  
Maternal Nutrition

0697 Effects of poor maternal nutrition during gestation on offspring prenatal muscle growth

2016 ◽  
Vol 94 (suppl_5) ◽  
pp. 333-334
Author(s):  
S. M. Pillai ◽  
A. K. Jones ◽  
M. L. Hoffman ◽  
K. K. McFadden ◽  
S. A. Zinn ◽  
...  
Keyword(s):  
Maternal Nutrition ◽  
Muscle Growth
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