Steroid Hormones How Steroids Work Chemistry and Conversion in Steroids Steroids in Insect Molt Cycles Human Development of Sexual Characters Steroids and Sex Change Environmental “estrogens” and their disruption of normal cycles

Molt Associated Hormones Bursicon – a protein from neurosecretory cells in brain that promotes cuticle development in newly molted adults Ecdysone – a steroid from the prothorasic glands produces growth necessary for molting Eclosion – a peptide from the brain that induces the emergence from the pupa state Juvenile Hormone – fatty acid from the corpus allatum that inhibits metamorphosis Prothorasicotropin– PTTH – small protein freom the prothorasic gland that stimulates ecdysone release

In the 1950’s, ornithologists noticed a reduction in the survival of brown pelicans, gull and eagles. Egg shells were thin and birds showed no interest in nest building or courtship. DDT was linked to the decline. Another spill in a Florida lake in 1980 reduced the alligator birthrate by 90%. Young males have low sperm counts and small genitals.

DES (Diethylstibestrol) Introduced in 1938 to prevent miscarriage 5 million women world-wide treated DES linked to cancer in 1971 DES babies show higher levels of reproductive cancers, low sperm count, lessened sexual attraction, depression

PCBs introduced in 1929 as an additive for paints, lubricants, electrical junctions, copy machines. In 1964, PCBs identified almost everywhere by Soren Jensen. Banned in the US in 1976 Releated to reproductive defects and hermaphrodism in many animals including polar bears.

In 1940’s epidemic in Australia caused collapse of merino wool crop. Problem traced to a non-native clover that produced an estogen disruptor. Other plants that use estrogen disruptors in defense include sun flower, fennel, wild carrots, soy beans, and sweet potatoes