Rijnberk Ad, Kooistra Hans S, Mol Jan A
Department of Clinical Sciences of Companion Animals, Utrecht University, P.O. Box 80.154, 3508, TD Utrecht, The Netherlands.
Growth Horm IGF Res. 2003 Aug;13 Suppl A:S158-64. doi: 10.1016/s1096-6374(03)00076-5.
Over several millennia, humans have created hundreds of dog and cat breeds by selective breeding, including fixation of mutant genes. The domestic dog is unique in the extent of its variation in height, weight and shape as well as its behavior. It is primarily the relatively long persistence of high levels of growth hormone (GH) release at a young age that accounts for the large body size in giant breeds of dogs. Several of the endocrine diseases of humans are also known to occur as similar entities in dogs and cats. With some variations, this is true for conditions such as diabetes mellitus and the hypofunction syndromes of the thyroid and adrenal cortex. Also, the hyperfunction syndromes of hypercortisolism and hyperparathyroidism in dogs and cats have many similarities with their human counterparts. The exception seems to be Graves' disease. This condition, which is due to production of thyroid-stimulating hormone (TSH)-receptor antibodies, has not been observed in dogs and cats. The very common form of hyperthyroidism in cats is due to toxic adenomas. In the 1980s it was discovered that in dogs exogenous progestins and endogenous progesterone can induce GH excess. This GH excess originates form the mammary gland and may give rise to acromegaly and insulin resistance. GH production by the mammary gland is not unique to the dog. It has become clear that cats and humans also express the GH gene in the mammary gland. There is increasing evidence that this locally produced GH not only plays a role in the morphologic changes of the mammary gland associated with the ovarian cycle and gestation, but that it is also involved in the development of breast cancer. In dogs, induction of mammary GH production by progestin administration allows for treatment of GH deficiency.
在几千年的时间里，人类通过选择性育种创造了数百种犬猫品种，其中包括突变基因的固定。家犬在身高、体重、体型以及行为方面的变异程度独一无二。主要是因为幼年时期高水平生长激素（GH）释放相对长期持续，才导致大型犬种体型巨大。人类的几种内分泌疾病在犬猫中也有类似情况。虽有一些差异，但糖尿病以及甲状腺和肾上腺皮质功能减退综合征等病症确实如此。此外，犬猫的皮质醇增多症和甲状旁腺功能亢进等功能亢进综合征与人类的同类病症有许多相似之处。例外情况似乎是格雷夫斯病。这种由促甲状腺激素（TSH）受体抗体产生导致的病症，在犬猫中尚未观察到。猫中非常常见的甲状腺功能亢进形式是由毒性腺瘤引起的。在20世纪80年代发现，在犬中，外源性孕激素和内源性孕酮可诱导GH过量。这种GH过量源于乳腺，可能导致肢端肥大症和胰岛素抵抗。乳腺产生GH并非犬类所特有。现已明确，猫和人类的乳腺中也表达GH基因。越来越多的证据表明，这种局部产生的GH不仅在与卵巢周期和妊娠相关的乳腺形态变化中起作用，而且还参与乳腺癌的发展。在犬中，通过给予孕激素诱导乳腺产生GH可用于治疗GH缺乏症。
