Lecture 1: Female Repro

Question 1

A 65-year-old woman was taken to the emergency department after fracturing her hip when stepping off a high curb. X-rays show a fracture at the head of the femur and also reveal very low bone density in general. Which of the following hormonal profiles for the pituitary-gonadal axis is predicted in the patient in terms of FSH, LH and estrogen?

Answer 1

[FSH] [LH] [Estrogen]

High High Low

Ovarian failure after menopause causes estrogen, progesterone, and inhibin levels to decrease to very low levels. The loss of negative feedback results in high levels of gonadotropin secretion by the anterior pituitary. This patient has osteoporosis, a common complication of sustained low estrogen.

Question 2

A blood sample is taken from a 27-year-old woman for hormone analysis. The sample contains low levels of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) and high levels of estrogen, progesterone, and inhibin. Assuming a normal 28-day menstrual cycle, on which day of the woman’s menstrual cycle was the blood sample taken?

Answer 2

Day 21

day 28 is the actual menses; A high concentration of estrogen, progesterone, and inhibin, all at the same time, indicates peak secretion from the corpus luteum about days 18-24. Negative feedback produces low LH and FSH.

Question 3

A stable derivative of cholesterol was synthesized as part of a drug discovery program. Which of the following properties is this new molecule most likely to have when injected into test subjects?

Answer 3

Circulates bound to plasma protein

Question 4

The luteinizing hormone surge measured during the ovulatory phase of the menstrual cycle results from positive feedback exerted by which of the following hormones.

Answer 4

Estrogen

A sustained high estrogen (in particular estradiol) concentration produces positive feedback stimulation of luteinizing hormone secretion by sensitizing gonadotropes to gonadotropin-releasing hormone.

Question 5

Ovarian granulosa cells were grown in primary cell culture in vitro. The cells failed to secrete significant amounts of estrogen when exposed to follicle-stimulating hormone (FSH) and luteinizing hormone (LH) until they were cultured together with ovarian thecal cells. A likely explanation for the failure of granulosa cells to produce estrogens when cultured alone is

Answer 5

lack of androgen precursors from which to produce estrogen

Estrogens are produced in a two-cell system of granulosa and theca cells. Theca cells provide androgen precursors under the influence of LH. Granulosa cells use androgens to synthesize estrogens, which is accomplished via FSH-stimulated aromatase activity.

Question 6

During the 12-hr period preceding ovulation, which of the following is true?

Answer 6

A surge of luteinizing hormone is secreted from the pituitary

Question 7

During the week following ovulation, the endometrium increases in thickness to 5 to 6 millimeters. What stimulates this increase in thickness

Answer 7

Progesterone from the corpus luteum

Question 8

What is the cause of menopause?

Answer 8

Reduced numbers of follicles available in the ovary for stimulation by gonadotropic hormones

By age 45 years, only a few primordial follicles remain in the ovaries to be stimulated by gonadotropic hormones, and the production of estrogen decreases as the number of follicles approaches zero. When estrogen production falls below a critical value, it can no longer inhibit the production of gonadotropic hormones from the anterior pituitary. Follicle-stimulating hormone and luteinizing hormone are produced in large quantities, but as the remaining follicles become atretic, production by the ovaries falls to zero.