L35: Growth Hormone

What percent of cells in the anterior pituitary are somatotrophs, which produce growth hormone?

Choose the incorrect statements.

SS stands for:

Somatotrophin is another name for growth hormone.

Growth hormone has been able to be produced in vitro since 1979.

Growth hormone is a [blank_start]peptide[blank_end] hormone. It is [blank_start]small[blank_end] (191 amino acids). The secretion of GH is [blank_start]pulsatile[blank_end] and has a [blank_start]daily[blank_end] rhythm which differs between males and females.

Growth hormone's half life in the blood is 20-25 minutes.

Growth hormone is an exception for [blank_start]peptide[blank_end] hormones because it travels in the [blank_start]blood bound to a protein carrier[blank_end].

Growth hormone releasing hormone neurons (GHRH neurons) in the [blank_start]hypothalamus[blank_end] are excited and release [blank_start]GHRH[blank_end] into the anterior pituitary gland where it stimulates [blank_start]somatotrophs[blank_end] to release growth hormone (GH). GH is released into the bloodstream where it stimulates [blank_start]insulin-like growth factor (IGF-1)[blank_end] production in the [blank_start]liver[blank_end]. IGF-1 feeds back to the hypothalamus where it [blank_start]inhibits[blank_end] more release of GHRH and stimulates [blank_start]somatostatin (SS)[blank_end] to inhibit release of [blank_start]GH[blank_end] by the anterior pituitary gland.

Choose the correct statements.

Growth hormone is essential for [blank_start]brain development[blank_end] until around age 8, rapid growth of [blank_start]height[blank_end] in two separate periods, and growth of [blank_start]reproductive organs[blank_end] around puberty.

Growth hormone receptor is a single molecule found in the membrane that does not require activation.

Which of these is not a long term effect of growth hormone?

Stimulation of mitogenesis via IGF-1 is a direct effect of growth hormone. Stimulation of protein synthesis in muscle by is an indirect effect of growth hormone.

Short term effects of growth hormone are always direct.

Choose the correct effects of GH on metabolism(short term effects).

Other hormones important for [blank_start]growth[blank_end] are thyroid hormones, insulin, cortisol, and estrogen/testosterone. Thyroid hormone [blank_start]increases[blank_end] the basal metabolic rate and is essential for [blank_start]nervous system[blank_end] development. Insulin and [blank_start]cortisol[blank_end] increase [blank_start]glucose[blank_end] metabolism. Estrogen/testosterone are essential during [blank_start]puberty[blank_end].

Endocrine disorders can be due to too little GH ([blank_start]hyposecretion[blank_end]) or too much GH ([blank_start]hypersecretion[blank_end]). An [blank_start]excess[blank_end] of GH can cause gigantism or acromegaly. Acromegaly is an excess of GH in [blank_start]adulthood[blank_end] which leads to thickening of [blank_start]bones[blank_end], and of soft tissues in the hands, feet and face. A [blank_start]deficiency[blank_end] can cause dwarfism. Endocrine disorders can also result from an issue in the GH [blank_start]receptors[blank_end]. Hyposensitive receptors [blank_start]give little or no response[blank_end] to GH and the effects are similar to hyposecretion. Hypersensitive receptors [blank_start]overreact[blank_end] to GH and have similar effects to hypersecretion.