Luteinizing Hormone in the Pituitary Gland of the Albino Rat: Concentration and Content as a Function of Sex and Age

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Abstract
Anterior pituitary concentrations and total content of LH were measured in both male and female rats from the neonatal period through sexual maturity. Concentration of LH in the female increased from 0.45 [mu]g/mg tissue at 10 days to 5.26 [mu]g/mg tissue at 30 days of age. By 40 days, in those females that had open vaginas, the LH concentration fell to 0.70 [mu]g/mg tissue. Following sexual maturation, the concentration in the female showed some fluctuations, depending on the stage of the estrous cycle, resulting in a mean concentration of 0.75 [mu]g/mg tissue. In the male, LH concentration was 0.20 [mu]g/mg at 5 days; this increased to 2.16 [mu]g/ mg at 30 days. At 40 days the content had fallen to 0.68 Mg/mg tissue. The adult male had 1.38-1. 55 [mu]g/mg tissue. Both males and females showed a peak concentration of LH at 30 days. In the female, total content of LH at 30 days was equal to the highest total content found in the adult cycling rat. From birth to vaginal opening the concentration of LH in the female was significantly greater than in the male. These potency relationships were reversed following sexual maturation. The adult male had 2 to 3 times the total content found at 30 days of age, even though the concentration was not significantly changed. These findings are discussed in relation to other studies of LH content and total gonadotrophin assays, both in relation to the phenomenon of puberty and the androgen sterilized female.