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Prenatal stress reduces estradiol-induced prolactin release in male and female rats
1Harvard Medical School, Department of Anatomy and Cellular Biology, Boston, MA 02115.
Insights
Prenatal stress significantly reduces estradiol-induced prolactin release in male rats. This endocrine disruption impacts sexual differentiation, affecting hormone regulation in males exposed to stress during development.
Area of Science:
- Neuroendocrinology
- Reproductive Biology
- Developmental Neuroscience
Background:
- Prenatal stress disrupts sexual differentiation and endocrine function.
- Estradiol-induced prolactin (Prl) release is a sexually dimorphic endocrine response.
Purpose of the Study:
- To investigate the impact of prenatal stress on estradiol-induced prolactin release in male and female rats.
- To examine sex-specific alterations in endocrine responses following prenatal stress.
Main Methods:
- Prenatal stress applied to pregnant rats via heat and restraint.
- Offspring cross-fostered to control dams and weaned.
- Gonadectomized animals implanted with estradiol (E2) and fitted with cannulae.
- Plasma prolactin levels measured over five days.
Main Results:
- Prenatally-stressed (P-S) male rats showed significantly lower plasma prolactin levels compared to controls.
- P-S males did not exhibit the typical daily afternoon increase in prolactin seen in control males.
- No significant differences were noted in females (data not shown in abstract).
Conclusions:
- Prenatal stress profoundly alters the sexually dimorphic prolactin response to estradiol in male rats.
- These findings highlight the long-lasting effects of prenatal stress on neuroendocrine regulation and sexual differentiation.
Abstract:
Prenatal stress is a potent disruptor of the normal course of sexual differentiation, affecting both males and females. In the present study, we wished to examine a sexually dimorphic endocrine response, estradiol (E2)-induced prolactin (Prl) release, in prenatally-stressed (P-S) males and females. Sprague-Dawley female rats were timed-mated (+ sperm = Day 1). From gestation days 15-22 one group of females was subjected to a thrice-daily regimen of heat and restraint stress (0830, 1230, and 1630 hr) consisting of placing the rats into a Plexiglas restraint tube over which were poised two 100 W floodlights. Control females remained undisturbed throughout pregnancy. At parturition all offspring were cross-fostered to untreated, recently-parturient dams and weaned at 25 days of age. Separate groups of P-S and Control males and females were gonadectomized and, for males, paired testes weights and body weights were recorded. Four days later the animals were implanted with Silastic capsules containing E2, and fitted with intra-atrial cannulae. The following day, blood samples were taken at 0900, 1300, 1500, and 1700 hr for a total of five days. Beginning with the 1700 hr sample on Day 2, and with the exception of the 1500 hr sample on Day 3, P-S males had significantly lower plasma Prl values than Control males through Day 4, and at the 1500 hr sample on Day 5. Moreover, at no point did P-S males exhibit a significant daily afternoon increase in Prl values, whereas Control males did so on Days 2 and 4.(ABSTRACT TRUNCATED AT 250 WORDS)
