Hypothalamic-Pituitary Testicular Interrelations in Fetal Rats

Sex Difference in Development of Fetal Pituitary-Gonadal Axis

“…For instance, adrenalectomy of a fetal rat increased 2 days later the volume of the fetal hypophysis (Coetzee and Wells, 1957;Eguchi and Morikawa, 1967): fetal thyroidectomy elevated 2 days later the per cent of basophilic cells in the fetal anterior pituitary (Hwang and Wells, 1959;Eguchi and Morikawa, 1967): hypertrophy of fetal adrenals after maternal adrenalectomy occurred within 2 days (Cohen, 1965;Morikawa et al, 1968) and even within 1 day (Kashiyama, 1958). Also, in our previous study, castration of a fetal male rat elevated the per cent of basophilic cells of the fetal pituitary within 1 day (Nakai et al, 1972).…”

“…This would give a new line of evidence for the reciprocal relation between the pituitary and the testis before birth in the rat, in view of the studies by several workers who reported that the increase in the relative number of basophilic cells following castration was intimately related to the increased production of gonadotrophic hormones (Zeckwer, 1937;Guyer and Claus, 1937;Purves, 1961). Also in our previous study, fetal castration caused an elevation of the uptake of 3H-leucine in basophilic cells of the fetal pituitary, suggesting the increase of their protein synthesis (Nakai et al, 1972). Furthermore, fetal castration elevated the uptake of 3H -leucine in nerve cells of the arcuate nuclei of the fetal hypothalamus, suggesting that the hypothalamic control of the fetal pituitarytesticular axis already exists before birth (Nakai et al, 1971).…”

“…Hypophysectomy of a male rabbit of rat fetus by decapitation resulted in a definite shrinkage of testicular interstitial cells (Jost, 1951;Eguchi and Morikawa, 1968). Bilateral castration of a fetal rat induced a significant increase in the per cent of pituitary basophilic cells in which the protein synthesis was accerelated significantly (Nakai et al, 1972). However, little information is available regarding the reciprocal relation between the pituitary and the ovary before birth.…”