THE THYROTROPIC HORMONE IN THE PITUITARY OF THE ALBINO RAT DURING GROWTH, PREGNANCY AND LACTATION1

Abstract

The pituitaries were assayed in groups of day-old White Leghorn chicks. The Bergman-Turner chick units of hormone were detd. from the avg. wt. of the chick thyroids. The conc. of the hormone increased in both sexes during the period of rapid growth. The [female][female] contained about 50% as much hormone as the [male][male] during this period, and about 62% as much as the [male] per g. of fresh tissue in all wt. groups. In estrus and the first half of pregnancy the conc. was low, and increased during the latter part of pregnancy and during lactation.