e. Luteinizing Hormone. In the female, luteinizing hormone (LH), Interstitial
cellstimulating hormone (ICSH) joins with folliclestimulating hormone to stimulate
estrogen secretion. Luteinizing hormone also promotes the rupture of the follicle to
release the ovum so that it may be impregnated. In the male, it stimulates the
production of testosterone.
f. Luteotropic Hormone. In females, luteotropic hormone (LTH), Prolactin
promotes the growth of breast tissue and lactation. In concert with LH, it stimulates and
maintains the corpus luteum, which secretes progesterone and estrogens.
250. HORMONES OF THE POSTERIOR PITUITARY
a. Luteinizing Hormone ( Vasopressin).
(1) Blood pressure. If large amounts of antidiuretic hormone( ADH) are
injected into an animal, the arterial pressure rises appreciably.
(2) Renal tubule effect. This hormone increases the permeability of the
collecting tubules to water. Without ADH (diabetes insipidus), a person will lose large
amounts of water from the body fluids, but retain the electrolytes. In the presence of
ADH, a person keeps most of the water in the body but loses more electrolytes.
Luteinizing hormone keeps the body fluid diluted and a lack of this hormone
concentrates the body fluids.
(1) Contraction of uterus. Oxytocin in sufficient quantity causes the uterus
to contract and is therefore responsible, to a large degree, for initiating labor and birth.
(2) Milk ejection. Suckling stimulates the release of oxytocin that, in turn,
starts the flow of milk.
251. PINEAL BODY
The pineal body is a controversial structure and considerable research is being
conducted on this gland. It is thought to inhibit the onset of puberty in man because
certain individuals with damaged pineals show precocious (early) development of their
sexual organs. The pineal body is also thought to be important in maintaining patterns
and rhythms in animals.